Computation and Informatics in Biology and Medicine (CIBM) Seminar:

The prefrontal cortex (PFC) plays a central role in a diverse set of cognitive and behavioral processes, including sustained attention, working memory, and behavioral inhibition. In delayed response tasks that probe working memory and other PFC functions, fluctuations in spiking activity rates of PFC neurons are posited to reflect the maintenance of attentional processes, abstract rules, or past stimuli and events during delayed-response tasks of working memory. However very little is known about coding mechanisms that maintain this information for long periods of time across the delay period. Additionally, stress impairs higher cognitive processes dependent on the PFC. However, surprisingly, to date the actions of stress on PFC neuronal discharge in animals engaged in tasks of working memory also remain unknown.

In this talk, I will present neurophysiologic data recorded from the PFC of rats performing a delayed-response task of spatial working memory that refutes the predominant theories related to stress-induced cognitive impairment. In addition, I will present a model of the conditional intensity of neuronal spiking within the PFC that allows these neurons to maintain information for extended periods of time; spiking history predicted discharge (SHPD). This model is framed within the context of a generalized linear model to address several questions related to the actions of PFC neuron function and stress. First, to what degree does past spiking activity of PFC neurons predict or modulate ongoing activity of these neurons? Second, does stress have an overall impact on the predictability of PFC neuron discharge given a cell’s intrinsic spiking history? Third, do specific task components (i.e. delay-period vs. behavioral response) interact with or modulate SHPD during baseline and acute stress.